To give a little back, here is one solution to not having DAG/Molycote/whatever dry film lubricant made of unicorn tears to seal the tripower end throttle bodies. Let us get right to the tech. At the end I will explain how I got here. Prep your throttle bodies. I really should have taken a pic of how mine started out. They were filled with mud/rust/bugs and stuck. I brushed what I could off with water and then put them under white vinegar for a day or two, checking on them every once and while, giving them the occasional scrub with new green scotchbrite and old toothbrushes. I also used zep orange heavy duty degreaser. It brought them back from the grave. Gather your supplies... JB Weld MEK(acetone is similar, but evaporates faster) Graphite Powder Small Paintbrushes Screwdriver(a real flat duct tape sorta guy would probably use a br*** drift) Hammer Brake Cleaner Scotch Brite Pads Something to stir epoxy with and in The Tech... Mix JB weld Mix in Graphite Powder(I used about 1/6 the size of the epoxy amount. It is fluffy) Thin with MEK(Thin paint consistency is better than thick paint. I had to add more after messing with it a bit) Paint on throttle blades and bore Make a bunch of test piles of this mix with things stuck in it so you can monitor setup Come back 7 hours later Snap open throttle blades with screwdriver and hammer(mine are thick tripower blades. Thin faker end carb blades might bend) Hold open throttle and dust with graphite powder using another paintbrush Snap them a few times Return a day later and inspect for flashing that needs to be broken off with a screwdriver Enjoy your idle Throttle body painted with mix and materials Impact marks where I alternated sides striking with increasing force Red circle showing flashing to be removed Now to get the intake painted olds gold and installed! Next part will be how I got to using JB Weld and Graphite with MEK. Flame away!
Not from me, I knew this post would be good when I saw your avatar...my favorite stuff right there...J2. Those black outlines around the blades also show up on nice original ones I've had. I wondered what the factory had used. Do you know if the originals had the stuff just on the blades, or the bores also? .
The "correct" way to have perfect end throttle bodies would be to start with perfect machining and finish with perfect lapping. Yeah, we don't have that here in the real world. Second best would be to use the factory band aid fix of painting on DAG. DAG is a dry film lubricant. Dry film lubricants are resins and molybdenum or graphite. DAG isn't even the current good stuff. We have better materials for sealing throttle body blades now. They do not carry it at the corner hardware store. So why would you want to use JB Weld, Graphite and MEK? JB Weld is epoxy with aluminum and graphite. Sounds pretty close to the right stuff. Someone even posted here on the hamb about using JB weld and acetone. I am slow and dumb, so I used MEK for a longer working time. Thinner is better. How critical is the amount of graphite? Not critical at all. I tested a few different mixes. It all worked. I really used it to just darken it up a bit, but it probably helps. Graphite is Graphite and silica. Silica is used as an epoxy thickener, so it is all good. It is important to dust it with graphite after snapping it open. JB weld is not set after 6-8hours. How could I do it better? I started out by only wanting to paint, while closed, the edges away from how the blades opened. Being a total idiot, I painted both edges of the second bore I touched. I'll be damned if I was going to have it looked like an accident, so I painted all the edges, both sides. The factory application was only on the bottom, towards the intake. The better YouTube tech is painting the edges and only the sides away from how the blades opened. I was afraid of gluing the things shut, so I didn't bond the edges. I would do it that way the next time, since the break was clean and really nice. The flashing that needed to be removed was the only one. I thought those lumps might be a problem, so I removed all but that one by s****ing it off while wet with a knife tip. Being a dim bulb, I missed that one. The only critical parts of this operation are making sure the bore and blades are clean and prepped and making the 2 part jb weld mix as perfect 1 to 1 as possible and mixed before adding anything else.
Yes, mine had the original black sealer on the bottoms, towards the intake. I guess it was applied by mechanics in the field, so there were a lot of different techniques.
This is a video of the proper tech and factory unobtainium sealing material. With how quick and easy the factory DAG comes off, forget it! His painting technique was better than mine and I would do the painting this way with my mix and timing, if I did it again. YouTube "How To Seal Throttle Bodies on Pontiac Tri-power 2GC Carburetors" I forgot to put that I gave the bores and blades a final brake cleaner blast, quick p*** with scotchbrite and then another blast of brake cleaner to make sure the surface was prepped for bonding, but any good prep would do.
Is this going on a stock restored car? I was wondering about the vac secondaries, versus mechanical progressive. I read where the salesmen were told to steer people away from J2 standard trans, as the carbs kick in all-or-none, and it was softened by the A/T trans? I never drove one with vac. I wonder how it behaves, compared to progressive? Seems like there must be huge difference in drivability/and mpg? IDK .
Stock? mostly. Restored? Not even close. Mine is a hydramatic. For anyone who doesn't know, the end carbs operation makes sense if you look close at the center carb accelerator pump scissor lever and the vacuum switch. The part that is around 11 o clock actuates the vacuum switch when almost full throttle. The little part of the switch that moves is on the backside of it, between the switch and the fuel bowl. When that switch, which doesn't move much, is actuated, vacuum from the pump on top of the fuel pump goes to the diaphragm, which when the choke is off, yanks open both carbs due to the linkage on the other side tying the end throttle bodies together. There is no progressive use of the end carbs at all. If the choke is off and you hammer down, you get it all. Everything up to almost full throttle is just the center 2 barrel and drives like it, if you set it up correctly and follow this tech so you don't have vac leaks through the throttle bodies I was planning on running a progressive linkage, but I had all the original parts and they all worked. I was sure it wasn't so, but it was. Everything cleaned up and worked. It would be a sin to trash a piece of history. Plus, the J2 is awesome!
Do you think this might work on leaking throttle shafts as well? I have some 4gc's I revived from their rusty, buggy grave I just don't have the time/$ to have a machine shop rebush, and fabricate new shafts as new shafts are not available for 4gcs.
Hello, From experience with the three carbs on my 348 58 Impala...one thing I did was to put a small hose clamp on the vacuum hose from the center carb to the outer carbs. I was in a race with a guy who was pretty fast, but I knew I could easily beat him when my outer carbs kicked in to play. We were even off of the line and he held a 1/2 fender lead throughout the race. I was waiting for the outer carbs to kick in and just pull away from the other guy. We finished with about 1/4 of a fender between us and he won. I could not understand it as I did not feel the "kick" when the outer carbs always kicked in to play. Back at the drive in parking lot, we all opened our hoods and I found the vacuum hose just laying on the manifold. So, the whole time, I was a single carb racer without the help of the outer two carbs. I put the hose back on and checked out the carb engagement. The motor sounded super strong. The outers worked well. So, I asked the guy to race again... He looked at me and what I did to the motor and politely declined with a ..."Well, I beat you once...etc excuse." We never raced again... To this day, that guy laughs at the possible rematch, knowing he would have lost if we raced...check your hoses. Jnaki I tried a progressive manual linkage, but for a daily driver on the street and racing on the weekends, the progressive linkage was not a good fit. Poor gas mileage and always on the three carb during normal acceleration. But at the drags, you always knew the outer carbs would kick in to play.
Clunker, I don't think you want to try this trick on the shaft. Even if you got it to shear, you might never get the shafts out again. The bits I got on the shafts were accidents, because, once again, I am stupid. If I were perfect, the sealant would only be on the blades and bore. This is only to stop air leaking past the TB which would be like m***ive vac leaks for the center 2 barrel. It doesn't do anything for air coming in around the shaft. If I were looking for bandaids, I would smooth the casting edge and polish the inside of the levers and then wedge in an o ring and silglide. Vac leak solved... maybe. For a little while... This really is the false economy of rigging stuff with duct tape and bailing wire, or o rings and silicone grease. Might as well just do it right the first time and not worry about it again.
I just linked this to the old "Rocket Oldsmobile" thread that's running again. http://www.jalopyjournal.com/forum/threads/rocket-oldsmobile-v8-information-compiled.715390/page-8
Hi have a fish carburettor a rare size so I can't swap it out, the throttle plate can spin around so it is not sealing properly and when the mixture is correct even with the plate flat across the bore the idle speed is twice what it should be. Has anyone built up the edge with solder or something like that ? I am just looking for ideas Thanks
My setup is the large base early Pontiac ends with a stock large base center (350 sbc). The first round, i tried the stock setup on the ends, totally ****ed, no idle, poor everything else. I use progressive linkage and no choke on the center. Had a dude work the end bases, machined 'em, and i insisted he use the heavy ****erflys that are used in the ends. Again, ****. Over the many years I tried to get a 3x2 setup right, i never did because of a loss of vacuum causing the bad performance. Finally, Charlie Price at Vintage Speed built a base for the tri power ends using aluminum and br***. I leaped and boom-the solution. I got some of the very first ones he made and to this day they work perfect. No leaks, even after they're run all out, idle is still great. He still makes 'em, don't know what they sell for right now (think i gave a premium price) but if you want trouble free multi carbs on a chevy, this is the ticket. A bonus is the good mileage i get with the stock center. Just one caution if you decide to do this--careful on tightening the base, too much an it'll deform a little and cause a bind. Do just enough to seat it to the gasket. Its not a cheap way out but not too much in our hot rod world is. No, I don't own stock or recommend-just fyi.
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